Field of the Invention
The present invention relates to a light amount adjustment technique.
Description of the Related Art
An optical device such as a camera or interchangeable lens sometimes includes a light amount adjustment member such as an ND filter, IR cut filter, or deflection filter in order to adjust the light amount. Japanese Patent Laid-Open No. 2002-176573 has disclosed a device capable of switching filters to be used to adjust the light amount by linearly moving a filter holder integrally holding a plurality of filters.
The device disclosed in Japanese Patent Laid-Open No. 2002-176573 has an arrangement in which the plurality of filters are mounted as they are arranged in one direction in the filter holder, and all the filters are moved at once by a single moving mechanism. When the number of filters is increased, therefore, the length of the filter holder increases in proportional to the number of filters, and this makes miniaturization of the device difficult.